Minimally invasive actuable bone fixation devices

ABSTRACT

Apparatus for bone reinforcement, fixation and treatment of diseased or fractured bones including a supporting structure optionally coated with therapeutic agent is provided. The supporting structure or device may be collapsible upon deployment at the surgical site, and include fixation features such as anchors to securely position in place once deployed. Bone cement or other material may be provided to alternatively secure the positioned supporting structure for treatment. A lockable bone fixation device is described that comprises: a sleeve adapted to be positioned in a space formed in a bone; a guidewire adapted to guide movement of the sleeve; and an actuable lock adapted to secure the sleeve within the space of the bone from an end of the device.

CROSS-REFERENCE

This application is a continuation application of Ser. No. 11/383,269,filed May 15, 2006 by Nelson entitled Minimally Invasive Actuable BoneFixation Devices, to which application priority under 35 USC §120 isclaimed, and which claims the benefit of U.S. Provisional ApplicationNo. 60/682,652, filed May 18, 2005 entitled Method and System forProviding Reinforcement of Bones, each of which are incorporated hereinby reference in their entirety.

BACKGROUND OF THE INVENTION

The present invention relates to method and system for providingreinforcement of bones. More specifically, the present invention relatesto method and system for providing reconstructive surgical proceduresand devices for reconstruction and reinforcement bones, includingdiseased, osteoporotic and fractured bones.

Bone fractures are a common medical condition both in the young and oldsegments of the population. However, with an increasingly agingpopulation, osteoporosis has become more of a significant medicalconcern in part due to the risk of osteoporotic fractures. Osteoporosisand osteoarthritis are among the most common conditions to affect themusculoskeletal system, as well as frequent causes of locomotor pain anddisability. Osteoporosis can occur in both human and animal subjects(e.g. horses). Osteoporosis (OP) and osteoarthritis (OA) occur in asubstantial portion of the human population over the age of fifty. TheNational Osteoporosis Foundation estimates that as many as 44 millionAmericans are affected by osteoporosis and low bone mass, leading tofractures in more than 300,000 people over the age of 65. In 1997 theestimated cost for osteoporosis related fractures was $13 billion. Thatfigure increased to $17 billion in 2002 and is projected to increase to$210-240 billion by 2040. Currently it is expected that one in twowomen, and one in four men, over the age of 50 will suffer anosteoporosis-related fracture. Osteoporosis is the most importantunderlying cause of fracture in the elderly.

One current treatment of bone fractures includes surgically resettingthe fractured bone. After the surgical procedure, the fractured area ofthe body (i.e., where the fractured bone is located) is often placed inan external cast for an extended period of time to ensure that thefractured bone heals properly. This can take several months for the boneto heal and for the patient to remove the cast before resuming normalactivities.

In some instances, an intramedullary (IM) rod or nail is used to alignand stabilize the fracture. In that instance, a metal rod is placedinside a canal of a bone and fixed in place, typically at both ends.See, for example, Fixion™ IM (Nail), www.disc-o-tech.com. This approachrequires incision, access to the canal, and placement of the IM nail.The nail can be subsequently removed or left in place. A conventional IMnail procedure requires a similar, but possibly larger, opening to thespace, a long metallic nail being placed across the fracture, and eithersubsequent removal, and or when the nail is not removed, a long termimplant of the IM nail. The outer diameter of the IM nail must beselected for the minimum inside diameter of the space. Therefore,portions of the IM nail may not be in contact with the canal. Further,micro-motion between the bone and the IM nail may cause pain or necrosisof the bone. In still other cases, infection can occur. The IM nail maybe removed after the fracture has healed. This requires a subsequentsurgery with all of the complications and risks of a later intrusiveprocedure.

External fixation is another technique employed to repair fractures. Inthis approach, a rod may traverse the fracture site outside of theepidermis. The rod is attached to the bone with trans-dermal screws. Ifexternal fixation is used, the patient will have multiple incisions,screws, and trans-dermal infection paths. Furthermore, the externalfixation is cosmetically intrusive, bulky, and prone to painfulinadvertent manipulation by environmental conditions such as, forexample, bumping into objects and laying on the device.

Other concepts relating to bone repair are disclosed in, for example,U.S. Pat. No. 5,108,404 to Scholten for Surgical Protocol for Fixationof Bone Using Inflatable Device; U.S. Pat. No. 4,453,539 to Raftopouloset al. for Expandable Intramedullary Nail for the Fixation of BoneFractures; U.S. Pat. No. 4,854,312 to Raftopolous for Expanding Nail;U.S. Pat. No. 4,932,969 to Frey et al. for Joint Endoprosthesis; U.S.Pat. No. 5,571,189 to Kuslich for Expandable Fabric Implant forStabilizing the Spinal Motion Segment; U.S. Pat. No. 4,522,200 toStednitz for Adjustable Rod; U.S. Pat. No. 4,204,531 to Aginsky for Nailwith Expanding Mechanism; U.S. Pat. No. 5,480,400 to Berger for Methodand Device for Internal Fixation of Bone Fractures; U.S. Pat. No.5,102,413 to Poddar for Inflatable Bone Fixation Device; U.S. Pat. No.5,303,718 to Krajicek for Method and Device for the Osteosynthesis ofBones; U.S. Pat. No. 6,358,283 to Hogfors et al. for Implantable Devicefor Lengthening and Correcting Malpositions of Skeletal Bones; U.S. Pat.No. 6,127,597 to Beyar et al. for Systems for Percutaneous Bone andSpinal Stabilization, Fixation and Repair; U.S. Pat. No. 6,527,775 toWarburton for Interlocking Fixation Device for the Distal Radius; U.S.Patent Publication US2006/0084998 A1 to Levy et al. for ExpandableOrthopedic Device; and PCT Publication WO 2005/112804 A1 to MyersSurgical Solutions, LLC for Fracture Fixation and Site StabilizationSystem.

In view of the foregoing, it would be desirable to have a device, systemand method for providing effective and minimally invasive bonereinforcement to treat fractured or diseased bones.

SUMMARY OF THE INVENTION

One embodiment of the present invention provides a low weight to volumemechanical support for fixation, reinforcement and reconstruction ofbone or other regions of the musculo-skeletal system. The method ofdelivery of the device is another aspect of the invention. The method ofdelivery of the device in accordance with the various embodiments of theinvention reduces the trauma created during surgery, decreasing therisks associated with infection and thereby decreasing the recuperationtime of the patient. The framework may in one embodiment include anexpandable and contractable structure to permit re-placement and removalof the reinforcement structure or framework.

In accordance with the various embodiments of the present invention, themechanical supporting framework or device may be made from a variety ofmaterials such as metal, composite, plastic or amorphous materials,which include, but are not limited to, steel, stainless steel, cobaltchromium plated steel, titanium, nickel titanium alloy (nitinol), superelastic alloy, and polymethylmethacrylate (PMMA). The supportingframework or device may also include other polymeric materials that arebiocompatible and provide mechanical strength, that include polymericmaterial with ability to carry and delivery therapeutic agents, thatinclude bioabsorbable properties, as well as composite materials andcomposite materials of titanium and polyetheretherketone (PEEK™),composite materials of polymers and minerals, composite materials ofpolymers and glass fibers, composite materials of metal, polymer, andminerals.

Within the scope of the present invention, each of the aforementionedtypes of device may further be coated with proteins from synthetic oranimal source, or include collagen coated structures, and radioactive orbrachytherapy materials. Furthermore, the construction of the supportingframework or device may include radio-opaque markers or components thatassist in their location during and after placement in the bone or otherregion of the musculo-skeletal systems.

Further, the reinforcement device may, in one embodiment, be osteoincorporating, such that the reinforcement device may be integrated intothe bone.

In a further embodiment, there is provided a low weight to volumemechanical supporting framework or device deployed in conjunction withother suitable materials to form a composite structure in-situ. Examplesof such suitable materials may include, but are not limited to, bonecement, high density polyethylene, Kapton®, polyetheretherketone(PEEK™), and other engineering polymers.

Once deployed, the supporting framework or device may be electrically,thermally, or mechanically passive or active at the deployed site withinthe body. Thus, for example, where the supporting framework or deviceincludes nitinol, the shape of the device may be dynamically modifiedusing thermal, electrical or mechanical manipulation. For example, thenitinol device or supporting framework may be expanded or contractedonce deployed, to move the bone or other region of the musculo-skeletalsystem or area of the anatomy by using one or more of thermal,electrical or mechanical approaches.

An embodiment of the invention includes a lockable bone fixation devicecomprising: a sleeve adapted to be positioned in a space formed in abone; a guidewire adapted to guide movement of the sleeve; and anactuable lock adapted to secure the sleeve within the space of the bonefrom an end of the device. The sleeve can be configured to be flexible,have apertures, be expandable and/or be bioabsorbable. Further, thesleeve can be removable from the space within the bone, if desired. Thedevice is adapted and configured to access the space within the bonethrough an access aperture formed in a bony protuberance of the bone. Ina further embodiment, a second sleeve can be provided that is adapted tofit within the first sleeve. Where a second sleeve is provided, thesecond sleeve can be used to control a retractable interdigitationprocess or teeth. The sleeve can accomplish this control by beingconfigured with slots or apertures along its length through which theteeth extend when the slots are positioned over the teeth. Once theteeth are exposed through the second sleeve, the teeth orinterdigitation process are adapted to engage bone. In still anotherembodiment of the invention, a cantilever adapted to retain the lockablebone fixation device within the space. Another embodiment of theinvention includes adapting the sleeve to be expanded and collapsedwithin the space by a user. In still another embodiment, the device isadapted to be delivered by a catheter. In yet another embodiment, thedistal end of the device is adapted to provide a blunt obduratorsurface. In still another embodiment of the device, the distal end ofthe device is configured to provide a guiding tip. In yet anotherembodiment of the device, the device is adapted to receive externalstimulation to provide therapy to the bone. In still another embodimentof the device, the device is adapted to receive composite material whenthe device is disposed within a lumen or opening within the body orbone.

In another embodiment of the invention, a bone fixation device isprovided that comprises: a first sleeve having a retractableinterdigitation process at a location along its length adapted to engagea bone; and a second sleeve sized adapted to activate theinterdigitation process of the first sleeve. The bone fixation devicecan be configured to provide a flexible first or second sleeve. Inanother embodiment, the first or second sleeve can be provided withapertures, can be expandable and/or can be fashioned from bioabsorbablematerials. In still other embodiments, either of the first or secondsleeve can be removable. In yet another embodiment of the invention, thefirst and second sleeve are adapted to access a space of the bonethrough an access aperture formed in a bony protuberance of the bone. Instill other embodiments, the second sleeve can be configured to providea retractable interdigitation process or teeth. Apertures can also beprovided in some embodiments, along the length of the device throughwhich the retractable interdigitation process engages the bone. Theapertures can, in some embodiments, be on the second sleeve. In someembodiments, the retractable interdigitation process can be adapted toengage bone when actuated by the second sleeve. In still otherembodiments, a cantilever retains the bone fixation device within aspace of the bone. Further, a first or second sleeve is adapted in someembodiments to be expanded and collapsed within the bone by a user. Instill other embodiments, the device is adapted to be delivered by acatheter or catheter-like device. The catheter may be a single ormultilumen tube. The catheter may employ methods or apparatus that poweror shape the device for introduction and placement. The distal end ofthe device in some embodiments is adapted to provide a blunt obduratorsurface. Additionally, the distal end of the device can have a guidingtip. In still other embodiments, the device is adapted to delivertherapeutic stimulation to the bone. In other embodiments the device isadapted to deliver therapeutic stimulation to the biological processeswithin bone. These processes are cellular in nature and providetherapeutic remedies to the health of the patient not related to bone.One such therapeutic application is anemia or hemophilia. In yet otherembodiments, the device is adapted to receive composite material whenthe device is disposed within a lumen.

In still another embodiment of the invention, a method of repairing abone fracture is disclosed that comprises: accessing a fracture along alength of a bone through a bony protuberance at an access point at anend of a bone; advancing a bone fixation device into a space through theaccess point at the end of the bone; bending a portion of the bonefixation device along its length to traverse the fracture; and lockingthe bone fixation device into place within the space of the bone. Themethod can also include the step of advancing an obdurator through thebony protuberance and across the fracture prior to advancing the bonefixation device into the space. In yet another embodiment of the method,the step of anchoring the bone fixation device within the space can beincluded. In still another embodiment of the method, a first sleeve anda second sleeve of the bone fixation device can be engaged to expand aninterdigitation process into the bone.

An aspect of the invention discloses a removable bone fixation devicethat has a single end of introduction, deployment, and remote actuationwherein a bone fixation device stabilizes bone. The bone fixation deviceis adapted to provide a single end in one area or location where thedevice initiates interaction with bone. The device can be deployed suchthat the device interacts with bone. Remote actuation activates,deactivates, reduces bone, displaces bone, locks, places, removes,grips, stiffens device, compresses, adjusts, axially adjusts,torsionally adjusts, angularly adjusts, and releases the devices duringits interaction with bone. A removable extractor can be provided in someembodiments of the device to enable the device to be placed andextracted by deployment and remote actuation from a single end. Thedevice of the invention can be adapted and configured to provide atleast one sleeve. Further the sleeve can be configured to be flexible inall angles and directions. The flexibility provided is in selectiveplanes and angles in the Cartesian, polar, or cylindrical coordinatesystems. Further, in some embodiments, the sleeve is configured to havea remote actuation at a single end. Additionally, the sleeve can beconfigured to have apertures. In still further embodiments, the sleeveis configured to minimize boney in-growth. Another aspect of theinvention includes a bone fixation device in that has mechanicalgeometry that interacts with bone by a change in the size of at leastone dimension of a Cartesian, polar, or spherical coordinate system.Further, in some embodiments, bioabsorbable materials can be used inconjunction with the devices, for example by providing specificsubcomponents of the device configured from bioabsorbable materials. Asecond sleeve can be provided in some embodiments where the secondsleeve is removable, has deployment, remote actuation, and a single end.Where a second sleeve is employed, the second sleeve can be adapted toprovide a deployable interdigitation process or to provide an aperturealong its length through which the deployable interdigitation process isadapted to engage bone. In some embodiments, the deployableinterdigitation process is further adapted to engage bone when actuatedby the sleeve. In some embodiments, the bone fixation device furthercomprises a cantilever adapted to retain the deployable bone fixationdevice within the space. The sleeve can further be adapted to beexpanded and collapsed within the space by a user. One end of the devicecan be configured to provide a blunt obdurator surface adapted toadvance into the bone. A guiding tip may also be provided thatfacilitates guiding the device through the bone. Further, the deployablebone fixation device can be adapted to receive external stimulation toprovide therapy to the bone. The device can further be adapted toprovide an integral stimulator which provides therapy to the bone. Instill other embodiments, the device can be adapted to receive delivertherapeutic stimulation to the bone.

The invention also includes a method for repairing a bone fracturecomprising: accessing a fracture along a length of bone through a bonyprotuberance at an entry portal; introducing the bone fixation deviceinto the medullary canal through the entry portal; bending the bonefixation device along its length to advance into the medullary space inthe bone; bending the bone fixation device along its length to traversethe fracture site; placing a flexible elbow in the medullary canal atthe fracture site; stiffening the bone fixation device; locking the bonefixation device to the bone; reducing the fracture with the bonefixation device in place in the medullary canal; locking the flexibleelbow to achieve intramedullary reduction of the fracture. The methodcan further include the step of introducing a guide wire into themedullary space through a bony protuberance at an entry portal.Additionally, the guidewire can be reamed through the bony protuberanceat an entry portal. The location of the reamed boney canal can bedetermined by the fracture anatomy and bone anatomy. In some embodimentsof the method, a sleeve can be advanced along the bone fixation device.In such embodiments, the sleeve can function to unlock the spikes fromthe fixation device. Once the spikes are unlocked from the fixationdevice, the spikes then fix the device to the bone. Locking butterflyrings can also be employed to lock the device to the bone. The butterflyrings can be locked to the fixation device in some embodiments.Additionally, the rings can be threaded over the device. In otherembodiments, a guide jig guides screws through the butterfly rings.Further self tapping screws lock the butterfly rings to the bone andbone fixation device. A set screw can also be used to lock the device atthe fracture site. The device can also be stiffened. In performing themethod of the invention, fracture fragments can be reduced.

Yet another aspect of the invention includes a barb-screw comprising asleeve, one or more teeth deployable at a distal end of the sleeve, andan actuable lock adapted to secure the sleeve within the space of thebone from an end of the device.

These and other features and advantages of the present invention will beunderstood upon consideration of the following detailed description ofthe invention and the accompanying drawings.

INCORPORATION BY REFERENCE

All publications, patents and patent applications mentioned in thisspecification are herein incorporated by reference in their entirety tothe same extent as if each individual publication, patent or patentapplication was specifically and individually indicated to beincorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIGS. 1A-B depict an actuable bone fixation device in a pre-deployed anddeployed condition;

FIGS. 2A-C depict views of a bearing segment suitable for use in anactuable bone fixation device;

FIGS. 3A-C depict views of a bearing segment suitable for use in anactuable bone fixation device;

FIG. 4A-F depict a retention segment suitable for use in an actuablebone fixation device;

FIGS. 5A-B illustrate an external actuator suitable for use in anactuable bone fixation device;

FIGS. 6A-D illustrate an alternate embodiment of an external actuatorsuitable for use in an actuable bone fixation device;

FIGS. 7A-C illustrate a pin suitable for use in an actuable bonefixation device;

FIGS. 8A-D illustrate a configuration of an outer sleeve suitable foruse in a bone fixation device;

FIGS. 9A-D illustrate an alternate configuration of an outer sleevesuitable for use in a bone fixation device;

FIGS. 10A-B illustrate another embodiment of an actuable bone fixationdevice in a pre-deployed and deployed condition;

FIGS. 11A-B illustrate yet another embodiment of an actuable bonefixation device in a pre-deployed condition, and deployed condition;

FIGS. 12A-C illustrate the proximal end of an embodiment of an actuablebone fixation device shown in FIG. 11, including component parts;

FIG. 13A-B illustrates a universal joint, or u-joint, suitable for usewith the devices of the invention;

FIG. 14 illustrates a flexible link assembly suitable for use with thedevices of the invention;

FIGS. 15A-B illustrate a configuration of a distal assembly;

FIGS. 16A-C illustrate a metaphyseal shaft;

FIG. 17 illustrates a metaphyseal locking flange;

FIG. 18 illustrates a metaphyseal locking screw;

FIG. 19 illustrates a metaphyseal set screw;

FIGS. 20A-B illustrate an alternative embodiment of a u-joint suitablefor use with the devices of the invention;

FIGS. 21A-B illustrate an alternative embodiment of a flexible linkassembly suitable for use with the invention;

FIGS. 22A-B illustrate a male pin suitable for use with a flexible linkassembly;

FIGS. 23A-B illustrate an alternative embodiment of a flexible linkassembly;

FIGS. 24A-B illustrate a sheath of a flexible link assembly;

FIGS. 25A-B illustrate an obdurator capture pin;

FIGS. 26A-B illustrate a flexible link male pin;

FIG. 27 illustrates a flexible locking pin;

FIGS. 28A-B illustrates a flexible link locking pin;

FIG. 29 illustrates an obdurator capture pin;

FIGS. 30A-D illustrate a diaphyseal anchor;

FIGS. 31A-B illustrated a removal tool;

FIG. 32 illustrates a device of the invention deployed in a radius bone;

FIG. 33 illustrates another actuable bone fixation device according tothe invention;

FIG. 34 illustrates a cross-section of a diaphyseal to metaphysealsection in a bone;

FIG. 35 illustrates a surgical access point into the intramedullaryspace;

FIG. 36 illustrates a device of the invention positioned within anaccess lumen;

FIG. 37 illustrates An actuable barb-screw according to the invention;

FIG. 38 illustrates a deployed barb-screw;

FIG. 39 illustrates a side view of a barb-screw;

FIG. 40 depicts a two part barb-screw according to the invention;

FIG. 41 illustrates a deployed actuable bone fixation device deployedwith transversely positioned actuable barb-screws;

FIG. 42 illustrates a deployed actuable bone fixation device deployedwith radially positioned barb-screws;

FIG. 43 illustrates a deployed actuable bone fixation device deployedwith mixed orientation barb-screws;

FIG. 44 illustrates a femur of a patient with an indication of accesspoints;

FIG. 45 illustrates a femur of a patient with a drill accessing theshaft;

FIG. 46 illustrates a femur with a coring reamer boring a hole in theshaft of the bone;

FIG. 47 illustrates a lavage system used with a bidirectional flow pathto remove debris from within the bone;

FIG. 48 illustrates an actuable bone fixation device within a bone;

FIG. 49 illustrates the device of FIG. 48 from a perspective view;

FIG. 50 illustrates a cross-sectional view of the device of FIG. 48;

FIG. 51 illustrates deployment of a cross-bone stabilization device;

FIG. 52 illustrates positioning of a reinforcement device at a desiredlocation;

FIGS. 53A-E illustrate implantation of a plurality of structuralreinforcement devices within a bone;

FIG. 54 illustrates an expandable device;

FIG. 55 illustrates a device coring into the upper trochanter region ofthe bone; and

FIG. 56 illustrates delivery of a device into the upper trochanter.

DETAILED DESCRIPTION OF THE INVENTION

By way of background and to provide context for the invention, it may beuseful to understand that bone is often described as a specializedconnective tissue that serves three major functions anatomically. First,bone provides a mechanical function by providing structure and muscularattachment for movement. Second, bone provides a metabolic function byproviding a reserve for calcium and phosphate. Finally, bone provides aprotective function by enclosing bone marrow and vital organs. Bones canbe categorized as long bones (e.g. radius, femur, tibia and humerus) andflat bones (e.g. skull, scapula and mandible). Each bone type has adifferent embryological template. Further each bone type containscortical and trabecular bone in varying proportions.

Cortical bone (compact) forms the shaft, or diaphysis, of long bones andthe outer shell of flat bones. The cortical bone provides the mainmechanical and protective function. The trabecular bone (cancellous) isfound at the end of the long bones, or the epiphysis, and inside thecortex of flat bones. The trabecular bone consists of a network ofinterconnecting trabecular plates and rods and is the major site of boneremodeling and resorption for mineral homeostasis. During development,the zone of growth between the epiphysis and diaphysis is themetaphysis. Finally, woven bone, which lacks the organized structure ofcortical or cancellous bone, is the first bone laid down during fracturerepair. Once a bone is fractured, the bone segments are positioned inproximity to each other in a manner that enables woven bone to be laiddown on the surface of the fracture. This description of anatomy andphysiology is provided in order to facilitate an understanding of theinvention. Persons of skill in the art, will appreciate that the scopeand nature of the invention is not limited by the anatomy discussionprovided. Further, it will be appreciated there can be variations inanatomical characteristics of an individual, as a result of a variety offactors, which are not described herein.

FIGS. 1A-B depict an actuable bone fixation device 100 in a pre-deployedand deployed condition. The bone fixation device 100 has a proximal end102 and a distal end 104. The proximal end and distal end, as used inthis context, refers to the position of an end of the device relative tothe remainder of the device or the opposing end as it appears in thedrawing. The proximal end can be used to refer to the end manipulated bythe user or physician. The proximal end may be configured such that aportion thereof remains outside the bone. Alternatively, the proximalend is configured such that it does not remain outside the bone. Thedistal end, thus, can be used to refer to the end of the device that isinserted and advanced within the bone and is furthest away from thephysician. As will be appreciated by those skilled in the art, the useof proximal and distal could change in another context, e.g. theanatomical context.

The bone fixation device is suitable for reinforcing and/or repairing abone. Further, the bone fixation device is adapted to be anatomicallyconformable. Still further, the bone fixation device is adapted to crossa fracture. Once actuated, the device anchors into a portion of the boneand then draws the bone segments effected by the fracture together.Kirshner or K-wires can also be used where there are additional fracturefragments.

The bone fixation device 100 has an actuator 110 at a proximal end 102.The actuator 110 enables a user to control the movement, insertion,deployment, removal, and operation of the device. The actuator 110 hasinternal threads (not shown) that engage threads 112 formed on a shaftor guidewire 120. The shaft 120 extends through a proximal bearingsegment 132, intermediate bearing segments 134 and terminates in adistal bearing segment 136. Interposed between the bearing segments onshaft 120 are anchoring segments 140. The bearing segments controltranslation and bending of the device 100. In some embodiments, thebearing segments can withstand, for example, up to 800 lb of axialloading force. The anchoring segments 140 have radially extending teethor grippers 142 that deploy upon actuation of the device 100 tointerlock the device with the bone, as explained below.

The outer sheath 150 is a component of the device 100. The outer sheathsurrounds a portion of the exposed length of the device 100. Slots 152are provided along its length that enable the teeth 142 of the anchoringsegment 140 to extend radially away from the external surface of thedevice 100 and into the bone when the device is actuated. The slots 152can also be adapted to promote or control bending of the device, as willbe appreciated below. In FIG. 1A, the device is depicted in apre-deployed state, i.e., prior to deploying the anchoring teeth. Priorto deployment, the teeth 142 of the anchoring segment 140 are positionedwithin the sleeve 150. When the device is actuated, as illustrated inFIG. 1B, the actuator 110 is rotated such that the drive shaft 120 isdrawn into the actuator 110. Drawing the drive shaft 120 into theactuator pulls the bearing segments and anchoring segments proximallywith respect to the sleeve 150, thus positioning the anchoring segments140 and teeth 142 adjacent the slots 152. In this embodiment, teeth 142are formed from an expansible material such as a shape memory alloy,such as the nitinol, to restore to an unconstrained position uponactuation of the device. This actuation results in movement of the teethradially away from the shaft of the device. The teeth are retractable asneeded or desired by reversing the direction of rotation of actuator110, thereby pushing the bearing segments and anchoring segmentsdistally with respect to the sleeve. The slope and angle of teeth 142help the edge of slots 152 cam teeth 142 inward to the position shown inFIG. 1A.

FIGS. 2A-C depict views of a bearing segment 230 (see also, bearingsegment 136 in FIG. 1) suitable for use in an actuable bone fixationdevice at, for example, the distal end. As illustrated in FIGS. 2A-B,the bearing segment, as depicted, has a substantially sphericaldimension, with a lumen 232 positioned therethrough for receiving adrive shaft or guide wire, such as shown above. The lumen, as depicted,has a first circumference at a first end 233 and a second circumference233A at a second end. First circumference, 233, is a distalcircumference (as oriented during implantation) adapted and configuredto accommodate a swaged or discontinuous intermediate interferinglocking feature. The swaged feature prevents proximal to distaltranslation of the distal bearing segment, 136 of the device, therebyretaining all proximal internal components of the device 100. FIG. 2Cillustrates the bearing segment in cross-section further illustrating asubstantially circular external shape with a first diameter 233corresponding to the first circumference and a second diameter 233Acorresponding to the second circumference. When positioned distally, thebearing segment can function as a blunt obdurator adapted to facilitatepenetration of bone.

FIGS. 3A-C depict views of another bearing segment 330 suitable for usein an actuable bone fixation device. The bearing segment, as depicted,has a substantially spherical dimension, with a lumen 332 positionedtherethrough. The lumen depicted in this embodiment has a constant, orsubstantially constant, diameter along its length suitable for receivingthe drive shaft or guide wire 120 of a device 100. Additional detents336, indentations or lumens can be provided. The detents 336 can beconfigured on the surface such that the detents would be positioned onopposing sides of the bearing segment 330, as depicted, without crossingor penetrating the lumen 332 formed to receive the drive shaft. Thedetents can be formed to receive pins, or be formed to provide anadditional lumen through the bearing segment, or compressed or swagedonto the drive shaft or can be configured in any other suitableconfiguration. As depicted in FIG. 3C, the lumen 332 traverses thebearing segment 330, while the detents are formed on opposing sides andoriented 90° from an axis around which the lumen 332 is positioned.Other orientations and configurations are possible without departingfrom the scope of the invention.

Turning now to FIG. 4A-F, a retention or anchoring segment suitable foruse in an actuable bone fixation device of the invention is depicted.FIGS. 4A-B illustrate perspective views of the anchoring segment 440prior to deployment of the teeth 442. The anchoring segment 440 isadapted to fit within the sleeve 150 (FIGS. 1A-B) and to have a centrallumen 444 through which a drive shaft 120 (FIGS. 1A-B) or guidewire canbe positioned. A portion of the exterior surface of the anchoringsegment 440 can be configured to form one or more teeth 442. The teeth442 can be formed integrally with the anchoring segment 440. The teeth442 and/or the anchoring segment 440 can be formed of any suitablematerial, including nitinol. Where a shape memory alloy is used, theteeth 442 can be configured to assume a pre-determined shape when theteeth are not constrained within the sleeve, as shown in FIG. 4E.Additional slots 446 can be provided along the length of the anchoringsegment. The slots 446 can be used to engage, for example, pinsextending from the outer sleeve to control rotational movement of theanchoring segment within the sleeve. Turning to FIG. 4D-E, the teeth 442are bent away from the exterior surface of the anchoring segment 440.FIG. 4F illustrates a cross-section of the anchoring device depictedherein wherein the teeth 442 are deflected away from the sides of theanchoring segment. The teeth may emanate from alternate surfaces andcross at the centerline of the lumen 444, thereby creating a longercantilever segment.

FIGS. 5A-B illustrate an actuator suitable for use in an actuable bonefixation device. The actuator 510 has a cylindrical body 512 with athreaded female interior 514 or any other configuration capable ofactuation for exposure of the teeth 442. A flange 516 is provided thatcan be used to anchor the device against a surface, such as bone.Additionally, the top surface of the flange 516 can be adapted to enablecontrol of the actuator 510 and the drive shaft 120 shown in FIG. 1. Oneor more apertures 518 can be provided to engage, for example, screws.The apertures 518 can provide a mechanism to anchor the device to thesurface of the bone (as opposed to just abutting the surface of thebone). The outer circumferential surface 517 of the flange 516 canfurther be provided with markings

513 or adapted to provide an indicator to facilitate deploying the teethby providing an indication to the user of the relative position of theteeth relative to the slots on the sheath and relative to the planewithin the bone. Thereby establishing the direction of flexibility ofthe device while in bone. Additionally, a central aperture 519 whichforms a keyway can be provided for engaging an additional tool or deviceto control the deployment of the bone fixation device. For example, thecentral aperture 519 can be in the shape of a slit to accept, forexample, the head of a flat head screw driver.

FIGS. 6A-D illustrate an alternate embodiment of an actuator 610suitable for use in an actuable bone fixation device. In the embodimentdepicted in FIGS. 6A-B, the central aperture 619 is adapted to engage atool with a threaded end. FIGS. 6C-D illustrate a top view and side viewof the actuator 610. Similar to the device depicted in FIG. 5, actuator610 has a cylindrical body 612 with a threaded female interior 614 orany other configuration capable of actuation for exposure of the teeth642. A flange 616 is provided that can be used to anchor the deviceagainst a surface, such as bone. Additionally, the top surface of theflange 616 can be adapted to enable control of the actuator 610 and thedrive shaft 120 (shown in FIG. 1. One or more apertures 618 can beprovided to engage, for example, screws. The apertures 618 can provide amechanism to anchor the device to the surface of the bone (as opposed toabutting the surface of the bone). Additionally, a central aperture 619which forms a keyway can be provided for engaging an additional tool ordevice to control the deployment of the bone fixation device. Forexample, the central aperture 619 can be in the shape of a slit toaccept, for example, the head of a flat head screw driver.

FIGS. 7A-C illustrate a pin 760 suitable for use in an actuable bonefixation device to prevent rotational movement of the anchoring segmentrelative to the sheath. The pin 760 has a head 762 adapted to engage aninterior portion of the sleeve and a neck 764 to fit within the slot inthe anchoring mechanism.

FIGS. 8A-D illustrate a configuration of an outer sleeve 850 suitablefor use in a bone fixation device. In the configuration depicted, c-cuts852 and 852A are used along the length of the sheath 850. The use ofc-cuts provides flexibility in the plane perpendicular to the pagedescribed along the central axis of the sheath. As depicted, two typesof c-cuts can be used, as opposed to a single type of c-cut shown inFIG. 1. At the distal end 804, c-cuts are paired at a location on thelength and extend, from opposite sides, toward a central plane of thesheath. The c-cuts enable the teeth of the device, 442 to extendoutward, away from the central shaft, into the bone. Toward a proximalend 802, c-cuts are shorter in height and extend across a central planeof the sheath (e.g. a plane in which the guidewire or control rodrunning through the center of the device would lie). Thus, from one sideview, the cuts have an s shape profile, as shown in FIG. 8C. The distalcuts provide flexibility as well as enabling the teeth, 442 to extendthrough the cuts when the device is actuated. The proximal cuts alsoprovide flexibility, but provide a different degree of flexibility as aresult of the orientation and design of the cuts. As depicted in FIG.8D, which is a cross-section taken along the lines D-D of FIG. 8C, theproximal set of c-cuts give the appearance that the sheath is segmented,while the distal cuts appear as opposing c-cuts. By this method theplanar preferential flexibility is established in a representative, butnot limiting, embodiment of the device. As will be appreciated by thoseskilled in the art, more than two-types of c-cuts can be used withoutdeparting from the scope of the invention.

FIGS. 9A-D illustrate yet another alternate configuration of an outersleeve suitable for use in a bone fixation device. In the devicedepicted, instead of providing the deep c-cuts on the proximal set ofcuts depicted in FIG. 8, spiral cuts 954 are provided. The spiral cutprovides flexibility in all directions and in all planes. As depicted,c-cuts 952 are used along at least a portion of the length of the sheath950

Turning now to FIGS. 10A-B another embodiment of an actuable bonefixation device 1000 in a pre-deployed and deployed condition isdepicted. This embodiment uses an outer sheath 1050 with two types ofc-cuts, as illustrated and described with respect to FIG. 8 above.C-cuts 1052 are used along the length of the sheath 1050. As describedabove, the use of c-cuts provides flexibility in the plane perpendicularto the page along the central axis of the sheath. As with FIG. 8, twotypes (or more) of c-cuts can be used, as opposed to a single type ofc-cut shown in FIG. 1. At the distal end 1004, c-cuts are paired at alocation on the length and extend, from opposite sides, toward a centralplane of the sheath. The c-cuts enable the teeth of the device, 1042 toextend outward, away from the central shaft, into the bone. Toward aproximal end 1002, c-cuts are shorter in height and extend across acentral plane of the sheath (e.g. a plane in which the guidewire orcontrol rod running through the center of the device would lie). Thus,from one side view, the cuts have an s shape profile, as shown in FIG.10B. The distal cuts provide flexibility as well as enabling the teeth,1042 to extend through the cuts when the device is actuated. Theproximal cuts also provide flexibility, but provide a different degreeof flexibility as a result of the orientation and design of the cuts.

FIGS. 11A-B illustrate another embodiment of an actuable bone fixationdevice 1100 in a pre-deployed and deployed condition. The device 1100has a proximal end 1102 and a distal end 1104. Section 1106 is the partof the device that is placed within the metaphyseal section of bone.Section 1106 can also be placed in other types of bone includingepiphyseal and diaphyseal. Section 1108 is the section of the devicethat sits within diaphyseal bone. The proximal end assembly 1110implements the interface to the metaphyseal bone. Also visible in FIG.11 are the metaphyseal locking flange 1112 and metaphyseal locking screw1114. Section 1130 is the universal joint that provides articulation andalignment. Section 1132 is the universal joint sheath. The flexible link1140 provides flexibility in the lateral medial plane. Section 1142 isthe flexible link sheath. Section 1150 is the outer sheath of the devicewith slot 1152. Section 1160 is the distal end assembly. Section 1162 isthe obdurator and Section 1164 is the distal end flexible link male pin.Section 1170 is the diaphyseal anchor with teeth 1172. At the distal end1104 and the proximal end 1102 the flexible link sections 1140 can beadapted to engage diaphyseal anchoring segments 1170. The anchoringsegments 1170, as depicted, fit snugly around the flexible link sections1130. Each diaphyseal anchoring segment 1170 can have one or more teethor grippers 1172 that are adapted to enable the teeth to interdigitatewithin bone when deployed. The teeth 1172 can be configured to enablethe teeth to deflect away from the anchoring segment 1170 and into thebone. The teeth 1172 extend at an angle to enable greatest anchoringwith the shortest length. As the teeth 1172 dig into the bone, the teethoppose torque and oppose proximal and rotational movement. The outersheath 1150 is positioned to maintain the teeth 1172 adjacent thesections of the device until the slots 1152 are adjacent the teeth 1172,at which point the teeth 1172 then can engage the bone. The distal end1104 can be adapted to form an obdurator 1162 to maintain and/or createthe space within the bone through which the device penetrates. Asillustrated in FIG. 11B, the teeth 1172 flare away from the device 1100when adjacent the slots 1152.

FIGS. 12A-C illustrates an embodiment of the proximal end assembly 1200.This assembly consists of the metaphyseal shaft 1210, one or moremetaphyseal locking flanges 1220, the metaphyseal locking screw 1230 andthe metaphyseal set screw 1240. The metaphyseal set screw 1900 isdepicted in additional detail in FIG. 19. The metaphyseal shaft 1210translates the fixative forces through the universal joint 1130 to thediaphyseal section 1108. The metaphyseal locking flange 1220 bears onthe metaphyseal shaft 1210. The metaphyseal locking screw 1230 threadsthrough the metaphyseal locking flange 1220, cuts into and retains themetaphyseal locking flange 1220 to the metaphyseal shaft 1210, andsecures bone, cartilage, animal tissue to the metaphyseal shaft 1210.

FIGS. 13A-B illustrates an embodiment of a universal joint 1300. Thisembodiment consists of a sheath 1310, (sheath 2200 is illustrated inadditional detail FIG. 20) and a diaphyseal pin 1320, (diaphyseal pin2100 illustrated in additional detail FIG. 21). The universal joint 1300allows the metaphysis section 1106 to have hemispherical rotationrelative to the axis of the diaphysis section 1108. The diaphyseal pin1320 connects the universal joint 1300 to the first proximal flexiblelink 1400.

FIG. 14 illustrates an embodiment of the flexible link assembly 1400.The flexible link assembly 1400 is comprised of the female pin 1420,(female pin 2300 is illustrated in additional detail in FIGS. 23A-B),male pin 1410, (male pin 2200 is illustrated in additional detail inFIGS. 22A-B), and the sheath 1430 (sheath 2400 is illustrated inadditional detail in FIGS. 24A-B). The male flexible link pin 2200 hasbearing surface 2214 that is captured within and slides axially andangularly within the sheath 2400. The female flexible link pin bearingsurface 2312 interfaces to the sheath bearing surface 2430. The bores2218 in the male and 2316 in the female pins accept the flexible linklocking pin 2800. The shape of the male flexible link pin 2200 andfemale flexible link pin 2300 allow medial to lateral flexibility priorto placement of the flexible link locking pin 2800. The bore 2218through the male flexible link 2200 accepts the flexible link lockingpin 2800. Upon insertion and proximal to distal actuation of theflexible link locking pin 2800, the male 2200 and female 2300 flexiblelink pins are thereby translated such that a locking force is impartedbetween the sheath 2400 and female flexible link pin. This lockingsystem imparts a resistive force to motion in the medial-lateral planeof the diaphysis and metaphysis. The bore 2218 through the male flexiblelink pin 2200 is shaped such that there is clearance up to 180 sphericaldegrees of angulation of the entire assembly, though 30 to 45 degrees ofangulation is typical. FIG. 30 show an embodiment of the diaphysealanchor 3000 which compromise teeth 3010 and an annular section 3020. Thediaphyseal anchor slips over and rigidly interferes with the shaft 2400of the flexible link 1400. The teeth 3010 of the anchoring segment 3000are designed for specific and maximal fixation to diaphyseal,metaphyseal and epiphyseal bone. The angulation coupled with rotationand shape of the teeth 3010 can take the form of pins, rods, rectangles,frustums of cones, pyramids or other polygons. The number of teeth 3010is typically two but not limited. In the embodiment shown the teeth 3010are oriented to prevent axial and rotational translation of the devicewhen deployed within bone. Sets of teeth 3010 can be juxtaposed toresist distal to proximal and proximal to distal axial translation. Itis known in the art that the intramedullary space is inconsistent ininternal diameter, the diaphyseal anchors 3000 can be specificallydesigned to accommodate these inconsistencies in internal diameter bychanging the shape of the teeth 3010.

FIGS. 15A-B illustrate an embodiment of the distal end assembly 1500.The distal end assembly 1500 is comprised of the obdurator or distalbearing surface 1510 (distal bearing surface 2500 is illustrated inadditional detail in FIG. 25), distal end flexible link male pin 1520(flexible link male pin 2600 is illustrated in additional detail in FIG.26), obdurator captive pin 1530 (obdurator captive pin 2700 isillustrated in additional detail in FIG. 27), flexible link locking pin1540 (flexible link locking pin 2800 is illustrated in additional detailin FIGS. 28A-B). The distal bearing surface 2500 is connected to theflexible locking pin 2800 and outer sheath 2900 in FIG. 29. Theobdurator captive pin 2700 limits the range of movement of the outersheath 2900 relative to the teeth 3010 of the anchor segments 3000.

FIGS. 16A-C illustrate an embodiment of a metaphyseal shaft 1600. Thebearing surface 1630 of this embodiment interfaces to the metaphyseallocking flange 1700, it can be smooth, serrated, knurled, splined,keyed, polygonal or elliptical. The connective surface 1610 connects themetaphyseal shaft 1600 to the universal joint 1300 of FIG. 13. Themetaphyseal shaft 1600 provides means to translate fixative forces fromthe metaphyseal section 1106 of FIG. 11 to the universal joint 1300.Within the metaphyseal shaft 1600 is a means to lock the proximalassembly 1200 of FIG. 12 to the diaphyseal section 1108 of FIG. 11through the universal joint 1300 and prevent 360 spherical degrees ofmovement perpendicular and parallel to the longitudinal axis of thediaphysis.

FIG. 17 illustrates an alternate embodiment of a metaphyseal lockingflange 1700. Screw hole 1710 accepts the metaphyseal locking screw 1800of FIG. 18. Opening 1716 accepts the metaphyseal shaft 1600 of FIG. 16.Windows 1712 exposes the metaphyseal shaft 1600 and accepts themetaphyseal locking screw threads 1810 and 1820 of FIG. 18 therebytranslating forces through metaphyseal locking screw 1800 to metaphysealshaft 1600 and locking metaphyseal locking flange 1700 to metaphysealshaft 1600. Opening 1716 allows 360 degree rotation of metaphyseallocking flange 1700 about the metaphyseal shaft 1600. Angle 1720 asdescribed by a line perpendicular to the axis of the shaft and thesurface perpendicular to the axis of the screw hole 1710 can be 0 to 180degrees. This embodiment is meant to be descriptive but not limiting.The function of the metaphyseal locking flange 1700, metaphyseal lockingscrew 1800 and metaphyseal shaft 1600 allow for translation of themetaphyseal fixation to diaphyseal fixation that is infinitelyadjustable in 360 spherical degrees in the axes parallel andperpendicular to the axis of the diaphysis.

FIG. 18 illustrates an embodiment of the metaphyseal locking screw 1800.The threads 1810 and 1820 of the metaphyseal locking screw can be of asingle pitch root in diameter or multiple pitch, root and diameters. Thethreads 1820 and 1810 can take on a variety of features such as smooth,serrated, knurled, splined, keyed, polygonal or elliptical. Themetaphyseal locking screw 1800 can be cannulated through its axis toallow deployment by guide wire.

FIG. 31 illustrates an embodiment of a deployment removal tool 3100 foruse with the implantable devices of the invention. The tool 3100consists of a handle 3110, a flexible shaft 3120 and threaded socket3130.

FIG. 32 illustrate a radius bone 3201 from an arm having a fracture3202, a radius bone with a device 3203 implanted therein, and across-sectional view of a portion of a radius bone with a deviceimplanted therein. While FIG. 32 shows the location of a fracture 3202in the radius bone 3201, it will be appreciated that the presentinvention and the various embodiments thereof can be applied tofractures of varying degrees and at any location within a bonestructure. Furthermore, it will be appreciated those skilled in the artthat the various embodiments of the present invention can be applied toany bone in an animal including human, and the nature of the fracturemay be single, compound or fragmented fractures due to external trauma,or due to bone related disease such as osteoporosis. As depicted in FIG.32, the device 3203, accesses the bone at a bony protuberance 3204through the trabecular bone. The device 3203 advances through thecortical bone 3205 and, as pictured, is positioned within theintramedullary space 3206 within the bone marrow or other intramedullaryconstituents.

FIG. 33 illustrates another embodiment of an actuable bone fixationdevice 3310 having a wire form outer sheath 3320 along at least aportion of the length. The wire sheath can be welded to a stainlesssteel hypotube, for example, and can be configured to provide the endsbe in a turned-out position to prevent rotation.

A challenge in bone fixation across the diaphysis to the metaphysis hasbeen securing the cancellous bone in the metaphysis. This bone issponge-like and can be brittle or vacuous, particularly in osteoporoticpatients. A physician must choose between rigid to rigid surfacefixation and rigid to porous surface fixation. One embodiment of asystem capable of achieving rigid to porous fixation in skeletal bone isdescribed here. FIG. 34 is a cross section of a diaphysis to metaphysistransition of one of the skeletal bones of an animal or human. Acancellous or porous bone 3401 of the metaphysis is depicted. Anintramedullary space 3402 is depicted along an axis of the bone. FIG. 34illustrates a portion of a bone 3403 having a transverse fracture and anoblique fracture bone chip 3404. The challenge in practice is to tiethese three bone fragments, one of the diaphysis and the two of themetaphysis together. Embodiments of this invention enable the formationof a foundation rigidly secured in all Cartesian, polar, spherical andcylindrical axes of the diaphysis. FIG. 35 demonstrates surgical accessto the intramedullary space 3502 after creating a lumen 3501 from themetaphyseal bone to the diaphyseal bone. The device, 3601, described inthe preceding invention description is placed in the lumen and deployedas shown in FIG. 36. FIG. 37 illustrates a novel barb-screw. Thebarb-screw consist of a tool interface such as a hex head, flat head,torx head, or Phillips head screw drive Feature 3701. Feature 3702 is athread that threads into and locks to the metaphyseal section of thedevice 3601 or through the metaphyseal locking flange 1700. The barbscrew is comprised of wires or filaments, 3703, of nickel titanium orother rigid metallic, polymer, or ceramic material capable ofdeformation over a significant strain without yield or fracture. In oneembodiment, the wires or filaments are beveled at the end 3704, tocreate a sharp or penetrating end. Upon removal of suppressive forcesuch as a sheath 3705 or actuation by thermal, electrical, or mechanicalmeans, the filaments undergo a physical change and change shape to 3801or other shape, as shown in FIG. 38. A plurality of wires or filaments3901 may be positioned along the length of the barb-screw as shown inFIG. 39. The wires or filaments may serve multiple purposes, such ascreating a thread to facilitate placement of the barb screw. Uponremoval of the restraining force or application of an external motiveforce the dual purpose screw feature, 4001, can then turn and arc tocapture bone as shown in FIG. 40. The barb-screw can be deployed throughthe device 3601, retained by the thread, 4001, to the device 3601, andcapture bone transverse 4101 to the placement of the device 3601 asshown in FIG. 41. The barb-screw can capture bone radially, 4201, fromthe device 3601 as shown in FIG. 42. A mixed mode of bone fragmentcapture may be utilized as well as shown in FIG. 43.

The actuable barb screw is adapted to provide a small diameter withgreat amount of surface area upon deployment; a combination of screw andbarb capture modalities; locking threads to the device 3601; and anactivation by removal of external force or by imparting energy to thedevice by thermal, electrical, optical, or mechanical means. Anyfrequency of the spectrum of electromechanical radiation may be used toimpart such energy to the system.

As will be appreciated by those skilled in the art, the actuable barbscrew can be configured to provide superior holding force and capture byemploying rigid materials that change their radius of capture area afterundergoing a change. Further, the barbs may be configured to bedisplaced as threads to aid insertion of the barb-screw.

Additional embodiments, methods, and uses are envisioned in accordancewith the inventive attributes. Thus, for example, the drill can be usedto bore an access opening into the trabecular (cancellous) bone at abony protrusion located at a proximal 4401 or distal 4402 end of FIG. 44of a bone having a fracture; where the proximal end in the anatomicalcontext is the end closest to the body midline and the distal end in theanatomical context is the end further from the body midline. Forexample, on the humerus, at the head of the humerus (located proximal,or nearest the midline of the body) or at the lateral or medialepicondyle (located distal, or furthest away from the midline); on theradius, at the head of the radius (proximal) or the radial styloidprocess (distal); on the ulna, at the head of the ulna (proximal) or theulnar styloid process (distal); for the femur, at the greater trochanter(proximal) or the lateral epicondyle or medial epicondyle (distal); forthe tibia, at the medial condyle (proximal) or the medial malleolus(distal); for the fibula, at the neck of the fibula (proximal) or thelateral malleoulus (distal); the ribs; the clavicle; the phalanges; thebones of the metacarpus; the bones of the carpus; the bones of themetatarsus; the bones of the tarsus; the sternum and other bones withadequate internal dimension to accommodate mechanical fixation. As willbe appreciated by those skilled in the art, access locations other thanthe ones described herein may also be suitable depending upon thelocation and nature of the fracture and the repair to be achieved.Additionally, the devices taught herein are not limited to use on thelong bones listed above, but can also be used in other areas of the bodyas well, without departing from the scope of the invention. It is withinthe scope of the invention to adapt the device for use in flat bones aswell as long bones.

In accordance with one embodiment of the method, an incision 4501 asshown in FIG. 45 may be made on the skin of the patient at a locationsubstantially aligned with, for example, a proximal or distal end of thefractured bone (e.g., an end of the bone where cancellous bone islocated). The incision thus allows the skin substantially surroundingthe incision at location to be pulled or folded back in order to exposethe end of the fractured bone. The location of the access site is chosenby the surgeon based upon the diagnosis of the best entry point for thevarious devices of the invention. Access points include-areas of thebone that are considered minimally invasive. These sites include theareas of the bones at the intersection at the elbow, knee, and ankle,i.e. the trabecular or cancellous bone located at the end of the longbones.

A drill bit may be operated 4502 by the surgeon to bore an opening tocreate a space within a central portion of the fractured bone. See, U.S.Pat. No. 6,699,253 to McDowell et al. for Self-Centering Bone Drill.Although, as will be appreciated by those skilled in the art, any toolcapable of boring through the layer of tissue and into the fracturedbone may be used without departing from the scope of the invention. Oneexample of such a device includes, but is not limited to, a coringreamer 4601 as shown in FIG. 46 which may be used to bore into the boneas discussed below. See, U.S. Pat. No. 6,162,226 to de Carlo Jr. forLong Bone Reamer with Depth Stop Indicator. The coring reamer in oneembodiment may be configured to harvest a bone plug from the accesspoint for future closure of the surgically created wound. This methodwould facilitate healing, and improve the surgical outcome in regards tostrength, infection, and immune rejection of any foreign body.

The drill or reamer can be operated along the length of the bone inorder to reach the location of the bone fracture. As would beappreciated by those skilled in the art, the use of a flexible reamermay require distal guidance 4602 to prevent inadvertent injury or damageto the surrounding bone. In order to provide such guidance, a wire, orother thin resilient, flexible entity of minimal cross sectional size,can be provided to provide such guidance. The guide wire is placedsubsequent to creation of the access site and exposure of the space. Asecondary access hole 4603 can be created distal to the initial access.The guide wire is then deployed using standard technique into the bonespace, across the bone from the proximal access hole to the secondaryaccess hole. Further, the device can use its distal end as an obduratorto create a path through the bone, through the intramedullary space,and/or across a fracture, is desired.

A centering entity 4604, may be used to “float” the guide wire away fromthe extremities of the inside feature of the space and bone. The guidewire and centering entity may be left in place throughout the procedureand may be present considerable advantages for subsequent cleaning, andplacement of the reinforcement device. The second distal access may beoptional. The centering entity, or visualization under fluoroscopy, mayobviate the need for the distal access. In this embodiment of the use ofthe guide wire, the centering entity can be used independently of thedistal access. Another embodiment eliminates both the distal access andthe centering device. In that embodiment, only the guide wire is used tocenter the reaming tool. In another embodiment the guide wire is notused. The reaming tool is centered by technique of visualization underfluoroscopy or other means.

Thereafter, a channel within the bone, such as within the intramedullaryspace, is created and is cleaned to remove the bone and fat debris priorto the deployment of the reinforcement device through the space withinthe fractured bone. Irrigation and cleaning of the channel created inthe bone would be accomplished using techniques known in the art. Forexample, irrigation can be accomplished using water, saline or ringerssolution. Solutions that include other solutes may also be beneficial;for example, solutions of having functional or therapeutic advantage, aswell as growth stimulation and anti-infection agents such as antibiotic,including gentomiacin.

A lavage system can also be used, such as a lavage system 4701 shown inFIG. 47 which includes bi-directional flow path tubing. The lavagesystem can be used to remove bone fragments and fat debris from space asa result of using the drill or coring reamer. In one embodiment, thelavage system includes an inflow of saline solution provided into thespace of the fractured bone, while a vacuum suction by the flow pathtuning removes the bone and debris fragments loosened in salinesolution. In this manner, the space within the fractured bone may becleaned and prepared for the deployment of the reinforcement device tothe fracture site of the bone. See, U.S. Pat. No. 4,294,251 to Greenwaldet al. for Method of Suction Lavage.

The coring reamer or drill can be used to create a space within thefractured bone, as well as past the location of the fracture itself Thelavage system can be similarly configured to clean the debris within thespace including at the location of the fracture. The reamer or drill maytraverse the fracture site independently or in conjunction with aprotective sheath across the fracture site. As will be appreciated bythose skilled in the art, the space may be reamed from both ends, from aproximal opening and a distal opening up to the fracture site.

As discussed above, in accordance with one embodiment of the presentinvention, the physical trauma to the patient is substantially minimizedin treating the bone fracture by limiting the incision to a relativelysmall location corresponding to the proximal end of the fractured bone,allowing faster patient recovery and wound healing.

This procedure can use a smaller opening than the procedure used for anintramedullary nail. Further, the device and its operation, minimizes oreliminates the risk of pain or necrosis of the bone.

Candidate materials for the devices and components would be known bypersons skilled in the art and include, for example, suitablebiocompatible materials such as metals (e.g. stainless steel, shapememory alloys, such a nickel titanium alloy nitinol) and engineeringplastics (e.g. polycarbonate). See, for example U.S. Pat. No. 5,190,546to Jervis for Medical Devices Incorporating SIM Memory Alloy Elementsand U.S. Pat. No. 5,964,770 to Flomenblit for High Strength MedicalDevices of Shape Memory Alloy. In one embodiment, the outer exoskeletonor sheath may be made of materials such as titanium, cobalt chromestainless steel. Alternatively, the sheath can be made of biocompatiblepolymers such as polyetheretherketone (PEEK), polyarylamide,polyethylene, and polysulphone.

As will be appreciated by those skilled in the art, the polymer orthermoplastic used to make any of the components of the device, such cancomprise virtually any non-radiopaque polymer well known to thoseskilled in the art including, but not limited to, polyether-etherketone(PEEK), polyphenylsolfone (Radel®), or polyetherimide resin (Ultem®). Ifdesired, the polymer may also comprise a translucent or transparentmaterial, or a combination of materials where a first material has afirst radiopacity and the second material has a second radiopacity.Suitable PEEK can include an unfilled PEEK approved for medicalimplantation. The devices and components can be formed by extrusion,injection, compression molding and/or machining techniques, as would beappreciated by those skilled in the art.

Other polymers that may be suitable for use in some embodiments, forexample other grades of PEEK, such as 30% glass-filled or 30% carbonfilled, provided such materials are cleared for use in implantabledevices by the FDA, or other regulatory body. The use of glass filledPEEK would be desirable where there was a need to reduce the expansionrate and increase the flexural modulus of PEEK for the instrument.Glass-filled PEEK is known to be ideal for improved strength, stiffness,or stability while carbon filled PEEK is known to enhance thecompressive strength and stiffness of PEEK and lower its expansion rate.Still other suitable biocompatible thermoplastic or thermoplasticpolycondensate materials may be suitable, including materials that havegood memory, are flexible, and/or deflectable have very low moistureabsorption, and good wear and/or abrasion resistance, can be usedwithout departing from the scope of the invention. These includepolyetherketoneketone (PEKK), polyetherketone (PEK),polyetherketoneetherketoneketone (PEKEKK), andpolyetheretherketoneketone (PEEKK), and generally apolyaryletheretherketone. Further other polyketones can be used as wellas other thermoplastics. Reference to appropriate polymers that can beused in the tools or tool components can be made to the followingdocuments, all of which are incorporated herein by reference. Thesedocuments include: PCT Publication WO 02/02158 A1, to VictrexManufacturing Ltd. entitled Bio-Compatible Polymeric Materials; PCTPublication WO 02/00275 A1, to Victrex Manufacturing Ltd. entitledBio-Compatible Polymeric Materials; and PCT Publication WO 02/00270 A1,to Victrex Manufacturing Ltd. entitled Bio-Compatible PolymericMaterials. Still other materials such as Bionate®, polycarbonateurethane, available from the Polymer Technology Group, Berkeley, Calif.,may also be appropriate because of the good oxidative stability,biocompatibility, mechanical strength and abrasion resistance. Otherthermoplastic materials and other high molecular weight polymers can beused as well for portions of the instrument that are desired to beradiolucent.

Moreover, the outer exoskeleton structure, or sheath, may be a hybrid ofmetal components to accommodate the interdigitation features or dietubular part of the exoskeleton.

In still other embodiments, the device or components can be coated withtherapeutic agents or can be configured from polymers with therapeuticagents incorporated therein.

The device may be of a variety of lengths and diameters. The length anddiameter of the device may be determined by the fracture site andpatient anatomy and physiology considerations. The length must traversethe fracture across its angularity to the internal diameter. Thediameter ranges from the minimum to the maximum internal diameter forthe space. Though not restricted to these values, the length may varyfrom 1000 mm to 1 mm and the diameter may range from 0.1 mm to 100 mm.These interdigitation features are designed to penetrate 25 to 75% ofthe cortical bone at the site of the fracture. The designs of the deviceallow for a multiple lengths of interdigitation in different devices andwithin the same device.

The interdigitation features, upon full deployment, may be configured toopen out and into the surrounding bone to hold in place the fragments ofthe fractured bone. This can be achieved with the use of an inner sleeve4901 as shown in FIG. 49. In one embodiment of the present invention,the cross bone fracture stabilization assembly may be removed after apredetermined period of time during which the bone at the fractured sitehas substantially and completely healed. The inner sleeve 4801 as shownin FIG. 48 is then removed and the guide wire 4802 may be used to removethe cross bone fracture stabilization assembly 4803 in one embodiment.Alternatively, within the scope of the present invention, the cross bonefracture stabilization assembly may be permanently positioned within thespace so as to remain integrally intact with the bone tissuessubstantially at the fractured site.

As will be appreciated by those skilled in the art, the device can beconfigured such that an outer sleeve is removable upon deployment of theinterdigitation feature (e.g. expansion of the teeth away from thecentral axis). In another embodiment, the inner sleeve 5001 as shown inFIG. 50 can be removed causing the teeth 5002 to collapse inward towardthe central axis of the outer exoskeleton or sheath 5003. In anembodiment according to this design, the device to bone connective forcewould be eliminated upon removal of the inner sleeve. The teeth ofexoskeleton or sheath either retract back towards the central axis ofthe device or upon pulling the device towards the proximal opening inthe bone, the teeth disengage from the bone. This allows facile removalof the device. In one embodiment, the outer exoskeleton or sheath may beremoved by applying a force opposite in direction away from the outerexoskeleton.

While the description above relates to cross bone deployment, thisstabilization device is suitable to communicate anatomical forces acrossany areas of weakened bone. The location of the weakened bone isidentified by suitable diagnosis. The cross bone stabilization device5101 as shown in FIG. 51 within the scope of the present invention maybe deployed across the region of weakened bone. Within the scope of thepresent invention, the cross bone stabilization device may be made fromlarge diameter for long bones or very small sizes for bones of the handor foot. The diameter and length of the device are designed for fixationof the bone internally.

After positioning the reinforcement device at the desired locationwithin the space so as to substantially be in contact, with the bonefracture, using a K-wire driver 5201 as shown in FIG. 52, the bonefragments are attached to the reinforcement device 5202 that is fullydeployed, properly positioned within the space and structurally expandedto substantially fill the space where it is positioned. K-wires 5203,i.e., thin, rigid wires, can be used to stabilize bone fragments. Thesewires can be drilled through the bone to hold the fragments in place. Aswould be appreciated by those skilled in the art, the k-wires can alsobe placed percutaneously (through the skin).

More specifically, upon complete removal of the introducer describedabove from the central aperture, the bone fragments can be attached tothe device by K-wires deployed using a K-wire driver so that thefragments are substantially and properly aligned with the bone structureguided by the reinforcement device during the recuperation process.Furthermore, optionally, bone cement, allographic bone, harvested bone,cadaver bone or other suitable bony matrices maybe introduced into thespace after removing the introducer to substantially fill the space fromthe incision site to the reinforcement device. Moreover, prior toclosing the incision site, a bone plug may be deployed at the opening ofthe space of the bone to substantially seal the bony matrix and/or toseal the space.

After the device has been implanted according to any of the techniquesdescribed herein, the incision site is closed with stitches, forexample, to allow the fracture, and the fragments to heal.

In another embodiment of the device includes a plurality of independentstructural members with inner or outer position across weakened orfractured bone. Though each independent structural member is placeduniquely in bone additional wires, threads, sutures may tie thesetogether across bone so that the plurality of structural members arelinked and form a rigid construction that resists anatomical and typicalpatient loading and forces. In FIG. 53 are shown examples 5301, 5302,5303 and 5304 of independent structural members connected by hightensile strength connective members. With this construction, very smallreinforcement and fixation devices may be constructed in situ.

In similar construction an expandable device 5401 as shown in FIG. 54 isenvisioned whereby the interdigitating interface to bone lies proximaland distal to the plurality of bars, rods, or other members that tietogether both ends.

In another example, the upper trochanteric region of the bone or otherregion of the musculo-skeletal system may be exposed and a hole may becored out of the femoral neck 5501 as shown in FIG. 55. Thereinforcement device (e.g., made of nitinol) is then delivered to thebore and expanded to fill the outside diameter of the hole 5601 as shownin FIG. 56. The inner diameter of the reinforcement device may be filledand pressurized with the bone cement. Alternatively, the inner diameterof the reinforcement device may be filled with the excised bone, boneplug or allographic bone 5602.

A corollary embodiment of the previously described art include axialtranslation from distal to proximal ends of the device thereby drawingbone and tissue together through shortening the axial distance distal toproximal. These embodiments have specific applications in fracturenon-unions, joint fusions and certain fractures.

The devices disclosed herein can be deployed in a variety of suitableways, as would be appreciated by those skilled in the art. For example,a provisional closed reduction of the fracture can be performed whereina 1.5 to 2 inch incision is made overlying the metaphyseal prominence ofthe bone. Blunt dissection is then carried to the fascia whereupon thefascia is incised. The surgical approach to the central aspect(anterior-posterior) proceeds by either splitting the tendon or ligamentor muscle longitudinally or by elevating structures of the bone in asubperiosteal fashion. The choice of the particular approach varies withrespect to the fractured bone that is being treated. A specialized softtissue retractor is placed onto the bone retracting the soft tissuesaway from the entry point of the bone.

A guide wire can then be drilled at an angle into the insertion pointalong the metaphyseal prominence. The angle of placement of the guidewire along the longitudinal axis of the bone depends on the fractureanatomy and particular bone being treated. The guide wire can then beplaced under fluoroscopic guidance. An optimally chosen reamer isintroduced over the guide wire opening the metaphyseal entry point. Bothdevices are then removed.

A curved guide wire is introduced across the open channel of themetaphysis and is advanced across the fracture site into the diaphysisof the bone. Sequential reaming appropriate for the particular device isperformed to prepare the diaphysis. The distance from the fracture siteto the entry point is estimated under fluoroscopy and the appropriatedevice is selected. The reamer is withdrawn and the device is introducedacross the guide wire into the metaphysis and across the fracture intothe diaphysis. Fluoroscopy confirms the location of the universal jointat the metaphyseal/diaphyseal fracture site.

The diaphyseal teeth of the device are deployed and the device isrigidly fixed to the diaphysis of the fractured bone distal to thefracture site. Any extension of the fracture into the joint can now bereduced in a closed fashion and held with K wires or in an open fashionvia a dorsal approach to the intra-articular portion of the fracture.Metaphyseal locking flanges with targeting outriggers attached are nowadvanced (in to the metaphyseal bone) across the metaphyseal shaft.Using the attached targeting outrigger, guidewires are now placedthrough the metaphyseal locking flanges. The guidewires are directedfluoroscopically to stabilize the intra-articular portion of thefracture and/or to stabilize the metaphyseal fracture securely. Holesare drilled over the guidewires with a cannulated drill bit. Then, selftapping screws are advanced over the guidewires to lock the bone to theshaft and metaphyseal locking flange. The device is now locked withinthe proximal and distal bone fragments (metaphyseal or diaphyseal) anddistal (diaphyseal) bone. This provides for rigid fixation of thecomminuted intra-articular fragments to each other, and the fixationbetween these screws interlocking in to the metaphyseal flange componentprovides rigid fixation of these intra-articular fragments in themetaphyseal region to the diaphyseal shaft as well. The extremity andfracture is now manipulated until a satisfactory reduction is achievedas visualized under fluoroscopy. Thereafter, the fracture is manipulatedunder fluoroscopic guidance in order to achieve anatomic alignment ofthe bone fragments. Once optimal intramedullary reduction is achieved,the universal joint is locked. The fracture is now fixed securely. Theguide wire is removed and the wound is closed repairing the periosteumover the metaphyseal entry point and repairing the fascia and closingthe skin. A splint maybe applied.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

1. A method for treatment of an elongate bone, an intermedullary spaceextending along an axis of the bone, the bone having a fracture, themethod comprising; forming an access opening traversing theintermedullary space at a placement angle to the axis of the bone;inserting a first end of a bone fixation device into the access opening,the bone fixation device having a flexible sleeve extending between thefirst end and a second end along a sleeve axis; advancing the bonefixation device from the access opening into the intermedullary space byflexing the sleeve in a plane along the sleeve axis; rigidly affixing asection of the bone fixation device to the bone adjacent the accessopening, wherein the section spans the placement angle and rigidlysupports the sleeve within the intramedullary space; locking the bonefixation device within the intramedullary space by rotating an actuatorof the bone fixation device, the actuator oriented along the accessopening and coupled with the second end of the sleeve by the section sothat the actuator rotates about an axis of the access opening disposedat the placement angle to the axis of the bone wherein an elongatestructure extends from the actuator and around the placement angle, theelongate structure having sufficient flexibility to transfer movementfrom the actuator to the sleeve when the placement angle is at leastwithin a range of at least 30 to 45 degrees, and wherein the locking ofthe bone fixation device imposes an axial load on bearing surfacesdisposed along the sleeve so as to stiffens the bone fixation device;deploying a plurality of teeth, with the elongate element and inresponse to rotating of the actuator, from an un-deployed configurationto a deployed configuration, the teeth in the un-deployed configurationdisposed within an outer surface of the sleeve, the teeth in thedeployed configuration extending radially outwardly from the outersurface of the sleeve through apertures in the sleeve and securing thesleeve within the intermedullary space of the bone.
 2. The method ofclaim 1, wherein the elongate structure rotates about the axis of theaccess opening adjacent the actuator and transmits rotation around theplacement angle so as to rotate about the sleeve axis within theintermedullary space during deployment, the rotation of the elongatestructure urging the plurality of teeth radially outwardly, and whereinthe placement angle is within a range from 30 to 45 degrees.
 3. Themethod of claim 2, further comprising advancing a guidewire through theaccess opening and into the intermedullary space so that a bend of theguidewire extends around the placement angle between the access openingand the intermedullary space, a guidewire lumen extending axially withinthe bone fixation device; and wherein the bone fixation device isadvanced axially while the guidewire is disposed within the guidewirelumen so that the guidewire axially guides the sleeve of the bonefixation device from the access opening, around the placement angle, andinto the intermedullary space.
 4. The method of claim 1, wherein thesleeve flexes sufficiently so that the lockable bone fixation deviceconforms anatomically to the bone, wherein flexing of the sleeve isaccommodated by the bearing surfaces disposed along the length of thesleeve, and wherein rotation of the actuator imposes the axial load onthe bearing surfaces so as to stiffen the lockable fixation device whenthe teeth are in the deployed configuration such that fixation of thefracture is effected.
 5. The method of claim 1 wherein each toothcomprises a flexible structure and deploying the teeth bends the teethradially from the un-deployed configuration to the deployedconfiguration, the bending of the teeth induced by threaded coupling ofthe actuator near the second end of the sleeve such that axial motion ofthe elongate structure is transmitted along the flexible sleeve to theteeth disposed at the first end.
 6. The method of claim 1, furthercomprising removing the bone fixation device from the intermedullaryspace by articulation of the actuator so as to withdraw the teeth intothe sleeve.
 7. The method of claim 1, wherein the bone comprises aradius bone, and wherein the access aperture is formed through alaterally oriented bony protuberance of the radius bone so as to accessthe intermedullary space within the radius bone.
 8. The method of claim1, wherein each tooth is included in an associated anchoring segment,the anchoring segments comprising annular bodies from which the teethextend, the annular bodies of the anchoring segments being separatedaxially and disposed within the sleeve, the sleeve having a cutextending circumferentially therethrough so as to flex axially betweenthe annular bodies when the bone fixation device is inserted from theaccess opening into the intermedullary space, the annular bodies beingurged axially by rotating of the actuator when deploying the teeth. 9.The method of claim 1 wherein the sleeve comprises a spiral cut throughthe sleeve and the sleeve flexes laterally in all directions when thedevice is advanced at the placement angle.
 10. The method of claim 1wherein the section comprises a universal joint with the elongateextending therethrough, and further comprising flexing of the universaljoint to correspond to the placement angle during insertion of thesleeve, and locking the universal joint so that the section rigidlysupports the sleeve within the intramedullary space.